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Turbine Services

Services are singletons within the Turbine Framework which have
pluggable implementation, and are capable of participating in the
Turbine startup and shutdown. As Services are Singletons, there is
only one instance of each service in the system. Memory or connections
are allocated once only and the internal state is common to all
requesting clients. Services can access ServletConfig at system
startup time to process relative paths and similar functionality, they
can also access RunData on the first Turbine doGet execution to get
the environment Turbine is operating under and with. Services can also
initialize themselves before they are requested by the client for the
first time. A Service that is never used will not allocate resources to
itself. A Service can also execute actions upon the system being
shutdown, such as closing open connections. The Singleton pattern also
allows for the Services to be accessed from anywhere within your code.

The Life Cycle of a Service begins with the Services constructor. A Service
does not do much in it's contructor. Especially it should not allocate any
costly resources like large memory structure, DB or Network connections, etc.
The Service may be in the properties file, but unless a client using the
application needs the Service in question, there is no point starting the
Service.

The services available with Turbine can be found in the
org.apache.turbine.services package. Please note that the
[TODO]'s below simply mean that these services need more complete
documentation, it does not mean that they are still waiting to be
implemented.

Assembler Broker Service
Is the Service which allows assemblers such as Screens, Actions, Layout and
Scheduled Jobs to be loaded.

Component Service
Initializes external components which implement the Stratum lifecycle
interface, e.g. Torque and Fulcrum. Any new components will use the
Avalon lifecycle and thus the Avalon Component Service.

Factory Service
A Service for the instantiation of objects with either the specified loaders or
default class loaders.

Intake Service
A service that provides input validation along with a standard
parameter naming framework.

JSP Service
The JSP Service is the set of classes that process JSP files inside the
Turbine Layout/Navigations and Screen structure.

Pool Service
A service for the pooling of instantiated Objects, allowing for the recycling
and disposal of Objects in the pool.

Pull Service
Manages the creation of application tools that are available to all templates
in a Turbine application. The tools can have global scope, request scope, session
scope or persistant scope within your application.

Resources Service
The Resources Service has been removed and replaced with commons-configuration. You
find some explanation how to use commons-configuration here.

RunData Service
Is the Service which manages the higher level operations surrounding
requests and responses.

Scheduler Service
This service manages the schedule queue giving Cron like functionality.
The ScheduledJob can be stored in a database or a properties file.

Security Service
A service for the management of Users, Groups, Roles and Permissions
in the system, allowing for those Objects to interact with either
Database or LDAP backends. The service also allows for the security to be managed
without a backend.

Servlet Service
Encapsulates the information provided by the ServletContext API,
and makes it available from anywhere in the code.

Session Service
Provides access to Session information for the current web context.

Template Service
The Service for the mapping of templates to their screens and actions.

Torque Security Service
This is an implementation of a Security Service which uses Torque
generated peers to access the required security information.

Unique ID Service
Allows for the creation of Context unique and pseudo random identifiers.

Upload Service
This service manages multipart/form-data POST requests, storing them
temporarily in memory or locally. The resultant Objects can be manipulated through
a FileItem Object.

Velocity Service[TO DO] The service for the processing of Velocity Templates from within
the Turbine Layout/Navigations and Screen structure.